Hello, I'm new here, but I think I know what this is - it's a dressing tool for grinding wheels. Have one in my shop.

Welcome to DC featherblu!!

And that’s a great guess....you may have this one.

Jeeks had guessed it is used to flatten a grinding wheel....but I looked up a “dressing wheel” and what it does is basically sharpens or roughs up a grinding wheel. If this is it, then Jeeks was really close!